In this chapter we examine the effects of mindfulness training on serum proinflammatory cytokine levels in chronic tension-type headache (CTH) sufferers. Method: Forty-three CTH sufferers participated in a randomized wait-list controlled trial of a mindfulness intervention for headache. Serum concentrations of cytokines IL1-β, IL-2, IL-6, IL-8, IL-12, IL-18, IFN-γ, MCP-1 and TNF-α were measured before and after treatment/wait-list control conditions. Results: Repeated Measures Analysis of Variance revealed that IL1-β, IL-6, IL-8, MCP-1 and TNF-α decreased from pre to post assessments in the treatment and wait-list groups, with no group or group x time effects. Conclusions: Mindfulness training compared to a wait-list control condition does not reduce serum cytokine levels in CTH sufferers.